Temperature Based Stress Analysis of Notched Members
Final rept. Sep 1976-Feb 1979
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The purpose of this effort was to develop and demonstrate a method of experimentally determining both elastic and plastic strain distributions in metallic materials. This was accomplished by recording minute temperature changes on the surface of the material as it was subjected to various loading conditions. Mathematical relationships relating these changes to the strain in the material was developed and verified. Much of the success of this effort was due to the development of thermocouple attachment and readout technique that recorded minute temperature changes 0.1 degree centigrade at ten millisecond sample intervals. This small time period sampling assures that heat has not been conducted away from the thermocouple attachment point. The thermocouples consisting of two .13 mm dissimilar metal wires were attached to the surface 0.1 mm apart by discharging a large capacitor grounded to the specimen. The small size permits the mounting of several thermocouples in a small area. The determination of plastic zone outlines is thereby facilitated.